The present invention relates to a pneumatic tire and a tire cavity resonance suppression device, and more particularly, to a pneumatic tire and a tire cavity resonance suppression device in which noise caused by cavity resonance is effectively reduced.
A cavity resonance phenomenon that occurs in a cavity formed between a tire and a wheel rim is a major factor of tire noise. For example, the cavity resonance phenomenon is concerned with noise around 250 Hz regularly heard during traveling or impulsive sound generated driving over gaps or the like of on a road.
As a technique for reducing noise caused by such a cavity resonance phenomenon, addition of a sound absorbing material in the tire to absorb resonance sound, and fixing of a shield to the rim to subdivide the cavity have been proposed. However, since the sound absorbing material is not basically designed to suppress the generation of cavity resonance, a sufficient noise reduction effect cannot be obtained by the sound absorbing material that can be fixed in the tire in practice. Besides, the fixing of the shield to the rim has a problem that rim assembling performance is deteriorated.
On the other hand, there has recently been made a proposal that a sectional shape of the cavity is changed in a tire circumferential direction to constantly change a resonance frequency with rotation of a wheel, whereby the cavity resonance sound is effectively reduced only by a slight improvement. However, a change in a structure of the tire or the rim is required in this method. Thus, production facilities must be greatly changed. Moreover, it is difficult to apply the method to the existing tires or rims.